ORCID Profile
0000-0002-4429-873X
Current Organisation
University of Adelaide
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Publisher: Elsevier BV
Date: 06-2023
Publisher: Copernicus GmbH
Date: 12-09-2023
Publisher: MDPI AG
Date: 29-03-2022
DOI: 10.3390/GEOSCIENCES12040154
Abstract: Continental rifts have a significant role in supercontinent breakup and the development of sedimentary basins. The Australian Adelaide Superbasin is one of the largest and best-preserved rift systems that initiated during the breakup of Rodinia, yet substantial challenges still hinder our understanding of its early evolution and place within the Rodinian supercontinent. In the past decade, our understanding of rift and passive margin development, mantle plumes and their role in tectonics, geodynamics of supercontinent breakup, and sequence stratigraphy in tectonic settings has advanced significantly. However, literature on the early evolution of the Adelaide Superbasin has not been updated to reflect these advancements. Using new detrital zircon age data for provenance, combined with existing literature, we examine the earliest tectonic evolution of the Adelaide Superbasin in the context of our modern understanding of rift system development. A new maximum depositional age of 893 ± 9 Ma from the lowermost stratigraphic unit provides a revised limit on the initiation of sedimentation and rifting within the basin. Our model suggests that the basin evolved through an initial pulse of extension exploiting pre-existing crustal weakness to form half-grabens. Tectonic quiescence and stable subsidence followed, with deposition of a sourceward-shifting facies tract. Emplacement and extrusion of the Willouran Large Igneous Province occurred at c. 830 Ma, initiating a new phase of rifting. This rift renewal led to widespread extension and subsidence with the deposition of the Curdimurka Subgroup, which constitutes the main cyclic rift sequence in the Adelaide Superbasin. Our model suggests that the Adelaide Superbasin formed through rift propagation to an apparent triple junction, rather than apical extension outward from this point. In addition, we provide evidence suggesting a late Mesoproterozoic zircon source to the east of the basin, and show that the lowermost stratigraphy of the Centralian Superbasin, which is thought to be deposited coevally, had different primary detrital sources.
Publisher: California Digital Library (CDL)
Date: 08-07-2020
Publisher: Cambridge University Press (CUP)
Date: 07-2023
DOI: 10.1017/S0016756823000390
Abstract: The glaciogenic nature of the Yudnamutana Subgroup was first recognized over a century ago, and its global significance was recognized shortly after, with the eventual postulation of a global Sturtian Glaciation and Snowball Earth theory. Much debate on the origin and timing of these rocks, locally and globally, has ensued in the years since. A significant corpus of research on the lithology, sedimentology, geochronology and formal lithostratigraphy of these sequences globally has attempted to resolve many of these debates. In the type area for the Sturtian Glaciation, South Australia’s Adelaide Superbasin, the lithostratigraphy and sedimentology are well understood however, formal stratigraphic nomenclature has remained complicated and contested. Absolute dates on the stratigraphy are also extremely sparse in this area. The result of these longstanding issues has been disagreement as to whether the sedimentary rocks of the Yudnamutana Subgroup are truly correlative throughout South Australia, and if they were deposited in the same time span recently defined for Sturtian glacial rocks globally, c. 717 Ma to c. 660 Ma. This study presents a large detrital zircon study, summarizes and compiles existing global geochronology for the Sturtian Glaciation and revises the formal lithostratigraphic framework of the Yudnamutana Subgroup. We show equivalence of the rocks that comprise the revised Sturt Formation, the main glaciogenic unit of the Yudnamutana Subgroup, and that it was deposited within the time span globally defined for the Sturtian Glaciation.
Publisher: California Digital Library (CDL)
Date: 02-04-2022
DOI: 10.31223/X5NH0G
Abstract: Continental rifts have a significant role in supercontinent breakup, and the development of sedimentary basins. The Australian Adelaide Superbasin is one of the largest and best-preserved rift systems that initiated during the breakup of Rodinia, yet substantial challenges still hinder our understanding of its early evolution and place within the Rodinian supercontinent. In the past decade, our understanding of rift and passive margin development, mantle plumes and their role in tectonics, geodynamics of supercontinent breakup, and sequence stratigraphy in tectonic settings has advanced significantly, however literature on the early evolution of the Adelaide Superbasin has not been updated to reflect these advancements. Using new detrital zircon age data for provenance, combined with existing literature, we examine the earliest tectonic evolution of the Adelaide Superbasin in the context of our modern understanding of rift system development. A new maximum depositional age of 893 ± 9 Ma from the lowermost stratigraphic unit provides a revised limit on the initiation of sedimentation and rifting within the basin. Our model suggests that the basin evolved through an initial pulse of extension exploiting pre-existing crustal weakness to form half-grabens. Tectonic quiescence and stable subsidence followed, with deposition of a sourceward-shifting facies tract. Emplacement and extrusion of the Willouran Large Igneous Province occurred at c. 830 Ma initiating a new phase of rifting. This rift renewal led to widespread extension and subsidence with deposition of the Curdimurka Subgroup, which constitutes the main cyclic rift sequence in the Adelaide Superbasin. Our model suggests that the Adelaide Superbasin formed through rift propagation an apparent triple junction, rather than apical extension outwards from this point. Additionally, we provide evidence suggesting a late Mesoproterozoic zircon source to the east of the basin, and show that the lowermost stratigraphy of the Centralian Superbasin, which is thought to be deposited coevally, had different primary detrital sources.
Publisher: Copernicus GmbH
Date: 23-03-2020
DOI: 10.5194/EGUSPHERE-EGU2020-3184
Abstract: & & The Adelaide Rift Complex is a large sedimentary superbasin in South Australia that formed resultant of Rodinia& #8217 s breakup and subsequent evolution of the Australian passive margin of the Pacific basin. It holds a globally significant and exceptionally well-preserved Neoproterozoic& #8211 early Cambrian succession. Much work has been done over the last century describing the lithostratigraphy and sedimentology of this vast basin. The rift complex contains evidence for major changes in Earth& #8217 s systems, yet, the rocks are poorly dated, and the sediment provenance, and link with tectonic evolution, is remarkably poorly known.& & & & This work provides a centralised database of the currently available, and previously unpublished, detrital zircon geochronology for the Neoproterozoic of the Adelaide Rift Complex, highlighting where the available data is from, and the stratigraphic and spatial gaps in our knowledge. By subjecting the U& #8211 Pb detrital zircon data to data analytical techniques, we provide a first look overview of the change in provenance, and subsequently (generalised) palaeo-tectonogeography that this suggests during the Neoproterozoic. These data show a change from dominantly local sources in the middle Tonian, to dominantly far-field sources as the rift-basin develops over time. The Cryogenian icesheets punctuate this with an ephemeral return to more local sources from nearby rift shoulders. This effect is particularly apparent during the Sturtian Glaciation than in the younger Marinoan Glaciation. In the Ediacaran, we see an increasingly stronger influence of younger (& Ma) detrital zircons from an enigmatic source that we interpret to be from southern (i.e. Antarctic) sources. We also note that we see a slight shift in the late Mesoproterozoic age peaks, from ca. 1170 Ma to ca. 1090 Ma, with a corresponding decrease in older ca. 1600 Ma detritus.& & & & This work forms the basis of continuing work to improve our understanding of the geochronology, provenance and palaeo-tectonogeography of the Adelaide Rift Complex.& &
Publisher: California Digital Library (CDL)
Date: 24-03-2022
DOI: 10.31223/X5N63H
Abstract: The late Tonian sequences of the Adelaide Superbasin were witness to the birth of the proto-Pacific Ocean during the breakup of Rodinia. Understanding the sedimentology and provenance of these rocks from across the basin is key to understanding both their deposition over ~70 million years, the local palaeogeography, and leads to a better understanding of the early development of the proto-Pacific Ocean. While the sedimentology of the Burra Group is well studied in most areas, provenance studies on these sequences using detrital zircon have been limited in scope and lack both spatial and temporal ersity. In this study we begin to address this knowledge gap. S les were taken from across the Adelaide Superbasin to understand both spatial and temporal related changes in provenance. Our findings highlight the necessity of this approach by uncovering both subtle, and abrupt significant changes in detrital zircon spectra for coeval s les from across the basin, and up-sequence in local areas. Our results highlight significant changes in provenance c. 790 Ma in the north of the basin, and c. 740 Ma in the south of the basin. This suggests a southward propagation of the rift basin, gradually opening to southerly sediment supply. Additionally, we posit the existence of an unrecognised source of c. 1000–900 Ma zircon to the north or northeast of the basin to account for latest Stenian to earliest Tonian detrital zircon in the Myrtle Springs Formation.
Publisher: Copernicus GmbH
Date: 12-09-2023
Publisher: Elsevier BV
Date: 11-2020
Publisher: figshare
Date: 2020
Publisher: Elsevier BV
Date: 03-2016
Publisher: California Digital Library (CDL)
Date: 23-07-2023
DOI: 10.31223/X50G9N
Abstract: The glaciogenic nature of the Yudnamutana Subgroup was first identified over a century ago, and its global significance was recognised shortly after, eventually culminating with the global Sturtian Glaciation and Snowball Earth theory. Much debate on the origin and timing of these rocks, locally and globally, has ensued in the years since. A significant corpus of research on the lithology, sedimentology, geochronology, and formal lithostratigraphy of these sequences globally has attempted to resolve many of these debates. In the type area for the Sturtian Glaciation, South Australia’s Adelaide Superbasin, lithostratigraphy and sedimentology have been well understood however, formal stratigraphic nomenclature has remained complicated and contested. Geochronology has also been extremely sparse in this area. The result of these longstanding issues has been disagreement as to whether the sedimentary rocks of the Yudnamutana Subgroup are truly correlative throughout South Australia, and if they were deposited in the same time window recently defined for Sturtian glacial rocks globally, c. 717 Ma to c. 660 Ma. In this study we present a large detrital zircon study, summarise and compile existing global geochronology for the Sturtian Glaciation, and provide an updated formal lithostratigraphy. We show equivalence of the rocks that comprise the revised Sturt Formation of the Yudnamutana Subgroup, and that it was deposited within the time span globally defined for Sturtian Glaciation.
No related grants have been discovered for Jarred Lloyd.